The present invention relates to a semiconductor device, and, for example, a semiconductor device having a regulator circuit that converts a power supply applied from the outside into an internal power supply to be supplied to internal circuits and an interface circuit that transmits and receives signals to/from the outside of the device.
In a semiconductor device, dies produced by the same design are mounted in packages that are different in the number of pins, or some functions of the semiconductor device are activated or inactivated. Accordingly, plural kinds of products whose functions apparently differ from each other are prepared using the dies produced by the same design, and it is possible to respond to various customer needs with the small number of kinds of dies. If the semiconductor device is prepared in such a way, the number of pads can be reduced by switching a function defined for one pad to another, and various products can be provided without changing the design of dies. Japanese Unexamined Patent Application Publication No. Hei 5 (1993)-74140 discloses an example of such a semiconductor device in which a function defined for a pad can be switched to another.
The semiconductor device described in Japanese Unexamined Patent Application Publication No. Hei 5 (1993)-74140 has internal circuits such as a memory element and a memory peripheral circuit, a regulator circuit provided between the internal circuits and an external terminal, and a low-impedance switch coupled parallel to the regulator circuit, and supplying of power to the internal circuits is selectively switched between the regulator circuit and the low-impedance switch.